Hi Kevin the problem with the fan bracket snapped i have never seen happen,its more than likely a one off.If you ever take the fan off mark around the brackets with marker to make it easier to realign after refit.
Regarding your overheating this is quite common,when the first 39 trucks came out there was problems with leaks from the fan shaft more so when shrink wrap got in,so they beefed up the seal,this made the fan a bit tight especially when new,so when the truck gets to temp the fan should start off slow then build up speed as the temp rises.It works off both engine temp+hyd temp through the module you can check operation with lap top.(if you have one).
Sometimes the fan won't start to turn and truck overheats,disconnecting the fan works but the fan then runs at full speed all the time.
If you remove the fan speed control valve by removing the 4 mounting cap screws and pull off the valve(nothing will fall out you may need to catch a bit of oil).
Put the valve in your vice when you look in the end you will see a circlip with a spring behind it,remove the circlip and fit a linde 8mm washer between the circlip and spring.(use one of the washers from the side cover this is exactly the correct size)this just lifts the valve off its seat.Then refit the valve to the fan motor,refit the plug and the fan will run at 400rpm when cold then speed up as needed when told to by the module.This is the recommended Linde mod and easy to do,
A bit long winded but hope this helps Herald.